Interpretive Summary: Flax (Linum usitatissimum L.) offers potential for a new crop for the US to improve farm income and supply industries a domestic source of this important natural fiber for textile, composite, and paper/pulp applications. However, retting is the major problem in processing flax stems for fiber. Work conducted by ARS and collaborators showed that the aromatic constituents that naturally exist in the stem can inhibit enzymes essential for retting and could therefore contribute to the problem of retting. Research is important in identifying a problem limiting retting and provides a strategy to enhance enzymatic retting as an environmentally friendly method to replace traditional retting methods.

Technical Abstract:
Flax (Linum usitatissimum) bast tissue was sequentially extracted using hexane, propanol, methanol and water as solvents. Extracts from the propanol, methanol and water steps were analyzed using reverse phase HPLC and **13C NMR. Results indicated that the bast tissue contains a large variety of aromatic constituents including flavonoids and hydroxy-methoxy cinnamic acids linked to oligosaccharides and hydroxy acids through glycosidic linkages. The effects of the extractives on polysaccharidase activities, determined using viscometry, indicated that these phenolic compounds inhibited cellulase and pectinase activities and, therefore, could influence retting.